This postdoctoral training program addresses a need in the field of Pediatric Critical Care to train scientific investigators focusing on issues that specifically affect critically ill children. These issues fall into areas of 1) the impact of the developing host on the pathogenesis of and recovery from critical illness and 2) the effects of critical illness on development. This proposal is based upon the assumption that the field is best served by training both M.D. and Ph.D. investigators, as early collaboration between these two groups will establish stronger links between basic research and the bedside. To facilitate these interactions trainees throughout the training period will participate in workshops, journal clubs and group discussions which will focus on the pathophysiologic processes of critical illness in the developing host. Mentors are senior academicians whose areas of service or research link to pediatric critical care. Synergy between mentors will be required to establish an environment for research projects that fit the special needs of pediatric critical care, since very few investigators work on basic pathophysiologic mechanisms of critical illness in the context of child development outside the neonatal period. The major training method is a research preceptorship and trainees are supported for two years but additional training with support from other sources is encouraged. This program addresses the unique educational needs of both the M.D. and Ph.D. fellows. For the M.D. fellows?, individual committees headed by his/her mentor, will supervise and guide the research experience. The committee will suggest necessary/desirable course work, approve final proposals, and ensure that potentially beneficial collaborations have been explored, and assess progress. Ph.D. fellows participate in a limited, highly focused educational series on the pathobiology of disease in the critically ill developing host to provide them with the framework from which they can explore relevant questions in their basic investigations. To assure cohesiveness and cross-fertilization of research and clinical expertise between M.D. and Ph.D. scholars, a series of workshops and series have been developed. Dr. Mariscalco and Dr. Smith as Co-Directors are responsible for the administration and direction of the program. Their collaboration will provide the necessary integration of basic and clinical issues for the proposed training, and foster a multidisciplinary approach for trainees. The Executive Committee meets to review scientific and operational aspects of the training program, select trainees, review the trainees? progress, and select potential new mentors. An external Advisory Committee meets yearly to ensure the program is meeting its stated objectives.